Electric shower not as hot as it used to be

[Glenn Proctor]

Hi

We've got an electric shower. It's made by Aqualisa, and (I'm not sure of the correct term here) it just pumps the water - it doesn't do any heating. There's a temperature control knob on the front as well as one for adjusting the flow.

It's about 3 years old and has always been fine, however over the last few months we've noticed it's not quite as hot as it used to be. Even on the maximum temerature setting, it's not as hot as the water coming out of the taps. I've confirmed this using a thermometer.

Any suggestions? I'm aware that electric showers have temperature limiters in them, but that wouldn't explain why it used to be OK, but isn't now.

We've had some plumbing done elsewhere in the house, so the mains stopcock's been off and on a few times. The only thing I can think of is that the cold water pressure coming into the shower is too high, and there's not enough hot water for it to "keep up" - could this be the reason?

Thanks in advance

Glenn.

[John Stumbles]

The cold supply should probably be off a separate tapping on the cold tank in the roof (though some shower mixers can cope with mains cold and gravity hot). Could be filter on the hot inlet to the shower getting blocked: this'll probably be in the pipe connecting into the mixer (i.e. impossible to get at :-).

Or (assuming it's thermostatic) the thermostatic mechanism could be getting out of kilter.

You could let the hot water go cold and check whether you get a good _flow_ from the mixer, set to max temperature. If you don't that'd suggest blocked filters, if you do it's likely to be the thermostatic mechanism.

You should be able to take it apart and clean it (though you may find O-rings don't seal well when you put it back together again) and you should be able to get a new themostatic mechanism innards for it from Aqualisa (which I hope would include any O-rings you need to replace in doing so).

[BigWallop]

Try turning the cold supply down a bit to the shower. You should have isolator valves at the pump. Choose the pipes that feed to the pump and not the one from the pump to the shower. The isolator valves are usually like straight connectors with a slot right in the middle to fit a screw driver in, but some systems have proper stopcock taps on them to make servicing the pump easier.

Turning the cold supply down a bit should increase the hot flow and so raise the temperature again.

This is the first thing I'd check in this weather. It's getting colder outside, and water being supplied to the house is also getting colder. With these changes in the supply temperature of the water, then things in the house can, and normally do, change their characteristics.

[Stuart]

I thought he said it was an ELECTRIC shower he has the problem with .?? Stuart

[BigWallop]

So this bit in the original post doesn't mean anything then?

"We've got an electric shower. It's made by Aqualisa, and (I'm not sure of the correct term here) it just pumps the water"

This comment, along with the fact that most Aqualisa Showers are thermostatic valves with shower heads attached, made me assume it was a shower with a pumped supply. Although Aqualisa do, do Instant Shower systems as well.

[Glenn Proctor]

Folks

Thanks for the advice so far.

To clarify: the shower does not do any heating of the water itself. It just mixes the existing hot & cold water supplies. The only controls are a thermostatic dial and an Off-On-Boost flow control knob. It's an Aqualisa, I think the Aquastream, as pictured & described here:

water feeds are into the rear of the unit so I'm not sure if I can do anything about adjusting the water pressure without dismantling the whole thing.

Glenn.

[BigWallop]

NO !!!! Whoa up there Glen. The pipes that supply the shower will, or better have, isolator valves on them, so that the shower can be serviced or repaired without turning all your water off. Please don't go dismantling your shower at this stage of the fault finding. We don't know if anything is actually broken yet. :-))

Trace the pipework back to the pump or the tanks from which they're supplied. Somewhere along these pipes should be taps, stopcocks or things called Service Valves. A service valve looks just like a straight plumbing connector, but it has a small slot cut into the middle of it. The slot actually takes a screwdriver and is used to turn the water off to the rest of the system so it can be serviced or repaired. Hence the name Service Valve.

There should be a tap on each side of the supply system, one for the hot, and of course, one for the cold. The cold water is now coming into the house much colder than it has been over the summer months, so the shower is more likely struggling to keep itself hot with a much colder water supply. If you turn the cold water supply pressure off a bit, then the shower will not be taking in as much cold and should then be able to balance the temperature again. So, you should get a hotter shower again.

Start looking along the pipework and try to find a tap, stopcock or a service valve on the cold water supply side. When you find it, turn it off a bit, not to much, until you can feel the shower getting hotter. This might be best done with two people, especially if the pipes are in an awkward spot, one to feel the shower temperature, while you slowly turn the cold supply down until you're shouted at.

Good luck with it.

[Glenn Proctor]

Heh, this was going to be a weekend project, so you've stopped me in time :)

I'm familiar with what you're talking about - there are some of them elsewhere in the house. I'm not sure where the ones controlling the shower feeds are - I'll have to do some detective work. I know the pipes run from the attic down to the airing cupboard in the bathroom where the hot water storage tank is, then under the bath and up the wall to the shower (they're embedded in the wall and tiled over).

Thanks for the clear advice - I'll have a go at the weekend and let y'all know how I get on.

Cheers

Glenn.

[Pete C]

Hi,

Sounds like the mains cold water is at too high a pressure compared to the tanked hot water. Closing the stopcock some may mitigate this but the best way to go if it is this problem is a pressure reducing valve.

cheers, Pete.

[Set Square]

I hope not! This unit is designed for stored water systems only - and needs to get its cold feed from the header tank, *not* from the mains. I presume that it *is* correctly plumbed?

If hot water isn't getting through properly, there could possibly be a partial blockage in the pipe. If this is the case, you may be able to clear it by disconnecting the hot supply at the unit, and back-flushing it with mains water.

Alternatively, there may be some adjustments inside the unit which limit how far the mixing valve can move in the hot direction. [It needs to move more in winter than in summer anyway, because the cold supply is colder]. Have you got an installation manual? If not, it would be worth contacting Aqualisa, who will probably send one to you. [As far as I can see, there isn't a downloadable version on their website].

[Glenn Proctor]

It does its feed from the cold tank.

Difficult (for me at least) as the pipes are in the wall and go into the shower unit from the back.

Yes I have an installation manual. It gives instructions as to how to disassemble it, but they're quite daunting to someone of my limited skills and experience!

Glenn.

[Pete C]

Hi,

Could be worth checking if that's OK with Mira. I would guess that the installer may have turned the stopcock down a bit to reduce the cold water pressure when it's running.

See if there is a service manual available from Mira or the website, it could have a section on fault diagnosis which would help, if not a google on shower faults this group would give lots of ideas.

If the shower has a stop on the controls it would be worth checking the thermostat has not drifted, making it too low.

cheers, Pete.

[Set Square]

Mira won't care! - It's an Aqualisa Aquastream!